Builder

I wonder how well the 3d printed parts will hold under stress. Please let us now once you have the machine up and cutting wood.

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I'm expecting it will hold pretty well -- it's all PETG, 50% infill with 3 perimeters and a concerted effort to have the stress points align horizontally and transfer most of their force to the extrusions. You can hit the side of this thing with a mallet and it won't move -- I tried it I'm more worried that the holes I tapped in the conduit for the supports won't hold -- it's only 16 gauge steel, so that's not even 2 full threads per support, and right now I only have 5 supports. Of course I can always add more, but that'll mean partially dismantling the machine to do so.

I'll definitely keep it up to date and let you know how it goes -- even if it doesn't go well. This is actually building on what I learned with some previous builds, and all the weaknesses I encountered before are mitigated in this design.. Hopefully there aren't too many new weaknesses!

Builder

Build is mostly complete and is pretty rigid, but my Chinese spindle is struggling to keep up.. I'm going to put a Makita compact router on it this weekend if all goes well. It's very rigid on the long axis and Z axis, but the plastic shows its limitations on the short axis.. It flexes in the YZ direction. Currently it's still pretty rigid, but it does flex if I put a lot a pressure on it. I plan to mitigate this by fixing an aluminum plate to the back once I have the capability to cut aluminum.

Builder

Builder

Loving this!
are you planning on posting a full-on parts list etc once you've sorted it all out? love to hear.
Also what thickness ply are you cutting at the moment? max thickness you've tried etc?
Some of the downloadable opendesk cnc plans call for 24mm py which I'd love to cut - but wondering how well you think your design would do at 24mm?

Builder

Loving this!
are you planning on posting a full-on parts list etc once you've sorted it all out? love to hear.
Also what thickness ply are you cutting at the moment? max thickness you've tried etc?
Some of the downloadable opendesk cnc plans call for 24mm py which I'd love to cut - but wondering how well you think your design would do at 24mm?

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Absolutely, I just haven't had time.. I have (accidentally) cut more than 24mm deep and it handled the cut just fine. I'm making this specifically for making 2.5D furniture, and the first few "real" things are going to be OpenDesk chairs The only issue I'm still working out is how to best handle surface mapping -- even if your cutting surface is flat, a 4x8 sheet of plywood won't be. I've got a little endstop mount for the Z axis printed, but haven't tested it out yet.. I'm thinking I'll just do a firmware bed height mapping before the cut. I'm not going to be able to use it for the next 2-3 weeks though, so I can't promise a date on that.

If you're looking to start building it, off the top of my head you'll need:

Builder

thats great, thanks for that. I'm in new zealand (metric...) which is great youre using mostly metric fasteners etc.
With the conduit though what overall outside diameter are you using? its easy enough to find thicker walled pipe which i assume would add more rigidity than the thin walled tube. id just have to make sure the 3d printed parts and tube match up is all, without changing stl files etc.
also, do you know the router model? i have a few compact makitas available here
Appreciate the replies by the way. cheers!

Builder

Nice, i can get an RT0700C which is the same i think the 01 is the US version.
pipe-wise i can get 40NB or 50NB easily. 40NB is 48.3mm OD and 50NB is 60.3mm OD.
Various wall thicknesses ranging from 2.3mm (super light) to 4.5mm (heavy).
I'm thinking light or medium which would be 2.9 or 3.2mm wall

your conduit is 2.197in. or 55.8mm OD and 0.065in. or 1.65mm wall

Aliexpress is probably my best best for the steppers, did you get any specific degree or amp rating?

Side note too - have you tried running it in a vertical orientation? or say, leaning on your shop wall VS taking up shop floor space - would it run?

Builder

Nice, i can get an RT0700C which is the same i think the 01 is the US version.
pipe-wise i can get 40NB or 50NB easily. 40NB is 48.3mm OD and 50NB is 60.3mm OD.
Various wall thicknesses ranging from 2.3mm (super light) to 4.5mm (heavy).
I'm thinking light or medium which would be 2.9 or 3.2mm wall

your conduit is 2.197in. or 55.8mm OD and 0.065in. or 1.65mm wall

Aliexpress is probably my best best for the steppers, did you get any specific degree or amp rating?

Side note too - have you tried running it in a vertical orientation? or say, leaning on your shop wall VS taking up shop floor space - would it run?

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Cool, I'll try to get that generated tomorrow. As for mounting sideways: I had originally intended to mount it at a 45 degree angle, but I was eager to get it done and didn't want to complicate things. I think it would do well mounted at an angle, but if you do you will want to get thick wall conduit.

Builder

What spindle did you use? I am looking at spindles for my next build. Considering a 800w water cooled.

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I have a 500W generic Chinese spindle.. It does alright with 1/8" bits, but it's really just too under-powered for wood, and it doesn't have an automatic speed control. I plan to reuse it in a smaller build for cutting soft metals, which it might be better for since it tops out at 12000 RPM.

Builder

I love to see folks using 3d printed structural parts. The strength you can get from PETG is really quite good. I like to print mine at 255-260 to ensure really good layer bonding. At $15 or less for a 1kg spool, and considering its engineering properties, PETG is a fabulous value. I have downloaded the files, and plan to start printing soon. Thank you so much for an awesome project!

Builder

I love to see folks using 3d printed structural parts. The strength you can get from PETG is really quite good. I like to print mine at 255-260 to ensure really good layer bonding. At $15 or less for a 1kg spool, and considering its engineering properties, PETG is a fabulous value. I have downloaded the files, and plan to start printing soon. Thank you so much for an awesome project!

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Yep, it really is a great material! It's not the most rigid, but there are ways to work around that

Can't wait to see how your build goes! Let me know if you need clarification on any of it

Builder

It will probably be awhile before I can get much of the build going. Funds are tight, as my wife just gave birth to our fifth child this summer. Hospitals are wonderful, but they sure know how to pile on the billing. At least it will give me time to get everything dialed in and printed.

Thanks!!
appreciate the effort in that. im finding PETG printing here pretty expensive, although not too sure what you guys are paying in the US?
im looking at around $400-500 in printed parts alone through local printers.

i keep seeing opendesk drop new designs so i'm itching to make this haha. Thanks @Spiffcow you're a legend

Builder

Thanks!!
appreciate the effort in that. im finding PETG printing here pretty expensive, although not too sure what you guys are paying in the US?
im looking at around $400-500 in printed parts alone through local printers.

i keep seeing opendesk drop new designs so i'm itching to make this haha. Thanks @Spiffcow you're a legend

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Going through printing services gets expensive pretty quick.. As much as I would love to have someone try out these parts, I'm not sure it's the best fit for someone who doesn't already have a 3D printer. That said, a decent 3D printer kit can be had in the ~$200 range, and PETG goes for $15-30 (in the US, don't know about NZ).. Might be a good way to maximize value

Builder

Thanks!!
appreciate the effort in that. im finding PETG printing here pretty expensive, although not too sure what you guys are paying in the US?
im looking at around $400-500 in printed parts alone through local printers.

i keep seeing opendesk drop new designs so i'm itching to make this haha. Thanks @Spiffcow you're a legend

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By the time you have gotten a handful of parts from a printing service, you are already beyond the price of a decent printer.
The material itself is quite reasonable. I purchase the blind packs (4 spools for $60, they pick the colors) from MakerGeeks, so it comes out to $15 per kilogram and free shipping in the US.
If you are at all interested, now is not a bad time to look into picking up a printer. They are quite a lot of fun.

Builder

That is a nice design. Am curious about your gantry trucks- I don't see any adjustments for the bearings, did you have trouble getting that to work / line-up properly? How many iterations were required to achieve a good result? What sort of play do you have between the overall truck / bearings and rail surface? Is it nice and tight or does it track loosely?

Builder

That is a nice design. Am curious about your gantry trucks- I don't see any adjustments for the bearings, did you have trouble getting that to work / line-up properly? How many iterations were required to achieve a good result? What sort of play do you have between the overall truck / bearings and rail surface? Is it nice and tight or does it track loosely?

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I did a couple small test pieces to measure the right diameter, but when making the entire piece I actually got it "good enough" on my first try. Maybe someday when I build another one I'll tweak the wall thickness a little, but I think I lucked out on this one to a large extent

So what I ended up doing is to undersize the expected opening by about 5%. The bolt through the center can tighten or loosen these a little bit, but the design is reliant on the flexibility of the plastic to pull against the rails. It's a tight fit, but it rolls smoothly and doesn't grind. I haven't used a pressure gauge, but it's pretty hard to get any flex on the side pieces from pushing on the tool head. I think a large part of the success in that respect is due to the very low center of gravity and low amount of leverage on the Z axis.